Slack adjuster for the foundation brakes of railway freight cars



July 19, 1960 P. G. STULTZ, JR

SLACK ADJUSTER FOR THE FOUNDATION BRAKES OF RAILWAY FREIGHT CARS Original Filed Dec. 5, 1955 2 Sheets-Sheet l ArroRNm July 19, 1960 P. G. STULTZ, JR SLACK ADJUSTER FOR THE FOUNDATION BRAKES OF RAILWAY FREIGHT CARS 1955 2 Sheets-Sheet 2 Original Filed Dec. 5,

INVENTOR P0: v 6. 6 TUL rz,J

fl aa m w mw E w k United States Patent C SLACK ADJUSTER FOR THE FOUNDATION BRAKES F RAILWAY FREIGHT CARS Posy G. Stultz, Jr., Roanoke, Va., assignor to Charles M. OBoyle, Wilmington, Del.

Original application Dec. 5, 1955, Ser. No. 550,939. Di-

vided and this application Jan. 28, 1957, Ser. No. 639,601

3 Claims. (Cl. 74-533) The present invention relates to slack adjusters for the foundation brakes of railway freight cars and has for its general object and purposes certain improvements over the prior Patent No. 2,675,894 granted April 20, 1954, to Charles M. OBoyle.

,The present application is a division of my prior application Serial No. 550,939, filed December 5, 1955, now abandoned.

While the present invention has the same objects as those stated in the prior patent aforesaid, it has certain additional objects which involve more particularly the overall shortening of the slack adjuster together with corresponding decrease in the cost of original production.

Another object of the present invention is to provide an improved slack adjuster in which the mode of operation is changed and simplified over that disclosed in said prior patent more particularly in that the rack bar is made stationary with the freight car or its truck while the housing carrying the pawl is made movable along the rack bar and is connected to the brake rigging whereby an adjustment of the housing relatively to the rack bar will accomplish a slack take-up operation in the brake rigging and correspondingly reduce piston travel in the brake cylinder whereby the linear limits of such piston travel may be kept within the maximum permitted by regulatory bodies which control the operations of braking systems.

A further object of the invention is to provide an inexpensive, simply-constructed slack adjuster of a minimum number of parts in which the housing is adapted for easy movement along the rack bar providing thrust takeup in the brake rigging in a direction more nearly in alignment with the member of the brake rigging to which the moveable housing is coupled.

With the foregoing and other objects in view, the invention will be more fully described hereinafter, and will be more particularly pointed out in the claims appended hereto.

In the drawings, wherein like symbols refer to like or corresponding parts throughout the several views:

Figure 1 is a side elevational view, with the floating ,lever shown in section, of the slack adjuster with the teeth of the housing held in interlocked position with the teeth of the rack bar.

Figure 2 is an end elevational view takenfrom the right hand end of Figure 1.

Figure 3 is a vertical transverse sectional view taken on the line 33 of Figure 1.

Figure 4 is a longitudinal sectional view taken through a portion of the device shown in Figure 1 and illustrating the floating lever and its pin connection in a subse- 2 Figure 6 is a horizontal longitudinal sectional view taken on the line 6-6 of Figure 1.

Referring more particularly to Figures 1 to 6 inclusive, the rack bar 22 is fixed by its lateral webs or brackets 25 to the center sill or other fixed part of the under-frame of the car, such rack bar 22 having teeth 23 that upquent position in which the teeth are freed and the housing tiltedto permit disengagement of its teeth from the teeth of the rack bar.

"shown in Figure 1; and a stand from the upper edge of the rack bar.

These teeth have inclined inner faces, which faces are disposed toward the center of the car and vertical or abrupt outer faces which are toward the end of the car.

The movable housing 27 is slidably supported on the rack bar and may comprise a top wall 28, an outer side wall 29 and inner upper and lower side wall sections 30 and 31 respectively which are spaced apart by the slot 32 to accommodate the webs or brackets 25 in the sliding movement of the housing 27 on the stationary rack bar 22.

One or more pawl teeth 77 project down from the inner side of the top wall 28 of the housing, such teeth 77 being complementary to the rack bar-teeth 23 so as to mate and interfit therewith in the manner shown in Figure l.

The floating lever 54, having the handle 54 is received in a lever slot 78 in the base portion of the housing 27. This lever slot 78 divides the base into a lower base member 79 and an upper base member 80. In these base members 79 and'80 are provided pin slots 81 and 82 which provide for lost-motion. The inner end of the lever slot 78 is open as shown at 83 to permit the housing to be fitted to the floating lever 54. The outer end of the lever slot 78 is closed at 84 and is provided with shoulders 85 and 86 which define outer ends of the pin slots 81 and 82.

A pin 55 pivotally couples the floating lever 54 to the movable housing 27, which pin has a diametrically enlarged head 55 that is wider than the upper pin slot 8 2, which condition is shown to best advantage in Figure 6. This will prevent the pin 55 from dropping down through the slot 82 and it is also for the purpose of having the outstanding under surface of the pin head 55 ride upon inclined surfaces 87 on the upper edges of lateral walls 88 and 89 which between them define the upper pin slot 82. These walls 88 and 89 are also provided with flat surfaces 90 at the lower outer ends of the inclined surfaces 87 and with rounded or oppositely inclined surface 91 at the inner or higher ends of the inclined. surfaces 87.

In the operation of the invention, Figure 1 shows substantially an initial or origin position of the movable housing 27 to substantially the extreme right hand end of the stationary rack bar 22. The floating lever 54 is at the right hand end of the lever slot 78 with the pin 55 in contact with the end walls 85 and 86 of the slots 81 and 82. In this position the head 55 of the pin 55 rests at the upper ends of the inclined surfaces 87 and the pin 55 is in its most elevated position, it being understood that this pin 55 slides freely up and down in an opening through the floating lever 54 and of course freely up and down through the pin slots 81 and 82. 1

Figure 4 and then continuing the pull to the left until the v brake shoes are brought against the wheels. Incidental to this left hand movement of the floating lever 54, the pin head 55 and the pin 55 will be permitted to descend by gravity down the inclined surfaces 87 and onto the flat surface 90, as shown in Figure 4. In fact the, lever 454 will not entrain the housing 27 to move therewith until the pin 55 engages the end walls 85 and 86 of slots 81 and 82. It will be understood that in the full line position. ofFigure lthe .upperrsurface .of. the head 5.5 .,of:,;the pin 55 will either directly :engage the lower surface :of thefixed rack bar 22 or suchsurfaces will :be closer .together than the heighto-f the teeth 77 and 23?. .In other words, in the .full line position of Figure 1 the pin head 55 will act as .a lock preventing disengagement of the rack bar and housing teeth during a brake application. ,It will.also prevent disengagement of these teeth on hopper cars when they are turned upside down .for dumping. However, after the lever 54 has completed its lost-moti0n movement the pin head 55 will be the dotted position of Figure v1 and therefore when the lever 54 ientrains the housing .27 to move to the left therewith, the inclined surfaces of the housing teeth 77 will ride up .on the inclined surfaces of the ,fixed rack :bar teeth 23 and thus the excess slack taken up in the brake rigging by the movement of the lever 54 to the left will be eliminated from the brake rigging as the housing teeth 27 will take a new position with respect to tthe'rack bar teeth 23". t

In this way excess slack :in the brake rigging which develops from time to time may be eliminated therefrom by short movements of the housing 27 relative to the fixed rack ,bar 22 in the left hand direction as looked-at in Figure 1. These movements may be in increments of one or more teeth and the movement of the housing .27 to the left will be proportional to the wear developing in the brake shoes so that the slack in the brake rigging .may be maintained atall times at a substantial ideal value which will permit the brake shoes, without regard to wear therein, to assume a preselected position away from the wheels whereby the piston in the brake cylinder will be able to make effective applications of the brakes without exceeding predetermined prescribed linear travel.

.After the floating lever 54 has been moved manually toward the left by the handle 54* as far as the handle may be pulled, the handle is released'so that the weight and tension of the brake rigging will pull the lever 54 back to the mouth end .83 of the lever slot '78, where the movement will be arrested by the pin 55 encountering the end walls 85 and 86 of the base members 79 and '80 which lie at opposite sides of the mouth 83. position is shown in full lines in Figure 1.

When the brake shoes have been worn down to a point where itbecomes necessary or desirable to discard the same and refit with new shoes, the housings 27 will ordinarily be in a position approaching the extreme left end of the stationary rack bar 22". Such housings 2,7 must be moved all the way back to the origin position at the right end of the rack bar 22 and for this purpose the teeth 77.must.-be raised clear :of the teeth 23'. This raised position of :the housing .is shown in Figure 4 and it is effected by -first moving the floating lever 54 to the left to disengage the head 55 of the pin from its locked position and then lifting the lever 54 so as to elevate therewith the housing into the position indicated in Figure 4, whereupon the entire housing may be freely slid to the right over the rack bar 22 until the same reaches the origin pointshownin full lines in 'Figuree 1, atwhich time the :pin head'55 is restored to its :upper position in which it has forced down the housing 27 and the teeth 7.7 into interlocking engagement with the rack bar teeth .23

=way freight' cars comprising a rack bar adapted to .be 'aifixed toa stationary part'of the -car,-a pawl housing longitudinally and vertically movable on the rack bar with freedom to move in slack take-up direction but restrained against movement in slack restoring direction, said housing having a lost-motion slot therein extending in the direction of longitudinal movement of the housing on the rack bar, said housing having an inclined surface adjacent theslot having its high portion atthe slack restoring end @of the slot, and a headed pin s'lidable longitudinally and vertically in the slot and adapted to be slidably :connected for movement .to a :movable part of the brake rigging and with 1116 head riding upon the .inelined--.sur-face,- said inclined surface -and ,pin head so positionednelatively to the rack :bar .thatswhen the head occupies the high portion of the inclined surface .such head engages the rack bar to restrain substantial upward vertical movement of the housing to an extent that would free the pawl from the rack bar and when the head is on the .low portion of the inclined surface such head is free of the .rack bar permitting vertical upward movement of .thelhousingand the release ofits pawl from [the rack 'bar.

2. A slack adjuster for the foundation brakes of railway freight cars comprising a rack 'bar adapted to be aifixed to .a stationary part of the car, a pawl housing slidable on the rack bar and also having a substantially vertical movement with respect to the rack .bar, .said rack bar and housing having teeth engaged and disengaged by the vertical movements of the housing, .said housing having alost-motion slot extending substantially parallel with the length of the rack bar and having slack take-up and slackvrestoring ends, said housing having an inclined surface adjacent the slot with its high portion adjacent the slack-restoring end of the slot and its low portion .adjacent the take-up end of the-slot, a coupling member for coupling a movable element of the brake rigging :to said housing and-slidable in the slot and adapted to abutthe ends thereof .to etfecta slack take-up movement of the housing and a limit stop on the slack-restoring movement of the member, said coupling member also having a substantially vertical movement relatively in the housing and slot in the general direction of the vertical movement of the housing with respect to the rack bar, said coupling member having a part riding on said inclined surface to effect said vertical movements of the coupling member and positioned relatively to the rack bar that when on said high portion to engage the rack bar and vcause interlocking engagement of said teeth and when on the low portion of the surface to disengage the rack bar to permit vertical movement of the housing to disengage the teeth.

3. In a slack adjuster, a rack bar, a housing having relative longitudinal and substantially vertical movements on the rack bar, said rack bar and housing having interlocking parts engaged and disconnected by said vertical movements, a coupling member for detachable connection to a movable element of the brake rigging and mounted in the housing for relative limited longitudinal and substantially vertical movements, said housing having an inclined surface with a high portion opposite said interlocking parts and a low portion displaced from the said interlocking parts, said coupling member having a part sliding on the inclined surface and'verticallyshiftable thereby incident to its longitudinal movement to move between said high and low portions of the inclined surface, the high and low portions of the inclined surface located relatively to the rack bar in order that the coupling member is disengaged from the rack bar when on the low portion to permit release of said interlocking parts and is engaged with the rack bar when on the high portion to lock the interlocking parts against release.

Nash Feb. 13,, 1934 Camp Feb. 13, 1934 

